This invention relates to an air supply mechanism for a vehicle seat, and to a method for the operation thereof.
German document DE 102 26 008 A1 discloses an air supply mechanism for a vehicle seat of an open vehicle with at least one air discharging opening which is provided in the upper region of the vehicle seat and via which the head, shoulder and neck region of the seat occupant can be subjected to an air flow in order to reduce undesirable draft phenomena. In this case, the air flow can be regulated by means of a control device and, when the air supply mechanism is switched on, is set as a function of an automatically detected external parameter value, for example, an external temperature, or a specified value which can be selected by the seat occupant, to an assigned basic value. From this assigned basic value, a further setting of the air flow takes place as a function of an automatically detected further parameter value, for example, the driving speed. The two parameter values serve to set a low, average or a high basic value of the air flow, which basic value is determined by an assigned blower speed of the fan and an assigned heating power of the heating element. On the basis of this basic value, the setting of the air flow then takes place as a function of the driving speed in such a manner that, as the driving speed increases, the air flow and therefore the blower speed and the heating power of the heating element are increased, and vice versa.
However, in the above-described conventional vehicle seat with seat heating system and ventilation device (air supply mechanism), there is the problem that, when the air supply mechanism is switched on, the seat heating system and the ventilation device are activated and, as a result, directly after the mechanism is switched on, relatively cool air arrives at the shoulder and neck region of the seat occupant, since the heating element is not yet at the full heating power. This results in the seat occupant experiencing a draft and therefore leads to a loss of comfort.
German document DE 198 42 979 C1 discloses a vehicle seat with seat heating system and ventilation device, in which, each time the seat heating system is switched on, the control unit simultaneously activates the ventilation device for a defined period of time after the seat heating system is switched on. In this case, the seat heating system and the ventilation device are switched on at full power, and the power of the ventilation device is reduced asymptotically to a predetermined final value within the period of time. This final value can either be zero or a value predetermined manually depending on the sensation of heat. This results in a specific combination of seat heating and seat ventilation in the heating-up phase of the vehicle seat, causing the rate at which the cushion heats up in comparison to just the heating of the seat to be doubled. The seat heating system comprises a plurality of electric heating wires which are laid in an upholstery padding of the cushion. The ventilation device has a plurality of miniature fans. The fans are arranged in air ducts integrated in the cushion and suck up air from the vehicle interior region located below the vehicle seat and blow it into a ventilation layer of the cushion located below the upholstery padding.
German document DE 197 03 516 C1 discloses a vehicle seat with a seat heating system and ventilation device, in which the control unit is connected on the input side to a temperature sensor arranged in the cushion and on the output side to the seat heating system and the ventilation device. The ventilation device has a plurality of miniature fans which are integrated in a cushion pad, suck up air from the vehicle interior region located below the vehicle seat and blow it into a ventilation layer which covers the cushion pad and is composed of a spacer knit. The seat heating system comprises a plurality of heating coils which are in each case assigned to a miniature fan and are arranged together with the latter in a respective air duct formed in the cushion pad. The control unit drives the ventilation device and the seat heating system in various combinations of fan and heating stages as a function of a current cushion temperature and a predetermined desired cushion temperature.
The vehicle seat which is disclosed in German document DE 199 53 385 A1 has a seat heating system and ventilation device. An operating device is provided for the manual actuation of the seat heating system and of the ventilation device. If the ventilation device is switched on manually, the control unit regulates the seat heating system automatically as a function of the temperature of the seat surface. The ventilation device and the seat heating system can be switched in a stepwise manner and/or continuously by means of the operating device. Regulation takes place within the defined limits set by the user via the operating device. In addition, it is ensured that supercooling does not take place by means of the ventilation device by, when the ventilation device is switched on, the heating device for heating the vehicle seat being regulated automatically as a function of the seat surface temperature.
Also in such a conventional vehicle seat with a seat heating system and a ventilation device, when the seat heating system and the ventilation device are switched on, the heating element is not yet at the full heating power. The seat occupant, therefore, experiences a draft, in particular in the situation in which the ventilation device is initially operated at the maximum level and is then slowly switched down to a predetermined value.
It is therefore the object of the present invention to develop an air supply mechanism for a vehicle seat and a method for the operation thereof so that, even directly after the air supply mechanism is switched on, the seat occupant does not experience any draft.
According to the invention, this object is achieved both by an air supply mechanism for a vehicle seat as claimed and by a method for the operation of an air supply mechanism for a vehicle seat as claimed. Advantageous developments of the invention are also claimed.
By starting control according to the invention of the fan directly after the air supply mechanism for a vehicle seat is switched on, the seat occupant does not experience an initial sensation of draft due to a powerful discharge of relative cold air, but rather feels a pleasant warmth even directly after the mechanism is switched on.
This and further objects, features and advantages of the present invention become obvious from the description below of a preferred exemplary embodiment in conjunction with the drawings.